The present invention relates to a sorting machine system for postal matter with a postal code (corresponding to a zip code).
Various automatic processing machines for postal matter have been recently developed along with simplification of works in post offices. One of the machines is a letter sorting machine (LSM) with an automatic postal code reader. In Japan, the postal code is expressed by an upper set of three digits and a lower set of two supplementary digits separated by a hyphen therefrom. In each post office, the postal matter are classified for about 1000 destination areas according to the upper three digits. Therefore, in order to classify or sort postal matter, a great number of bins corresponding to the destination areas must be prepared on the shelf part of the LSM. However, the bins can hardly be mounted in the LSM due to the size of the LSM and the installation space. Conventionally, a sorting shelf having about 70 boxes thereon has been used and manual sortation has been performed. Each postal matter is primarily sorted into the bins of the shelf corresponding to destination areas represented by the upper three digits of the postal code and corresponding to 13 groups of adjacent areas.
A technique for applying the primary and secondary sortations to LSMs has been considered. However, if LSMs are separately arranged for primary sortation and secondary sortations of each group, the efficiency of operating LSMs is lowered, resulting in high cost.